Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Description Of Business And Significant Accounting Policies [Line Items]
Maturity period of highly liquid investments	3 months
Maturity period of short term investment	1 year
Shipping and handling revenue	$ 786	$ 723	$ 664
Payment terms for end-users	30 days
Payment terms for distributors	60 days
Cost of lending disposable products to direct customers	0
Foreign currency transaction (losses) gains	(209)	115	(119)
Grant income	0	409	52
(Income) expense related to remeasurement of fair value of fully vested stock options	272	(179)	(23)
Company's expense related to the medical device excise tax	417
Options, restricted stock and performance based shares excluded from calculation of net loss per share	2,721	3,676	2,949
Recognized expense related to stock options and restricted stock	3,080	3,468	2,931
Unexercised shares of common stock held by non-employee consultants	38	38
Accrued non-employee stock options	350	78
Subsidiaries [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Foreign currency transaction (losses) gains	269	(83)	30
Computer and other office equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	3 years
Generators [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Depreciation	1,251	1,081	1,294
Carrying amount of loaned equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Net carrying amount of loaned equipment	$ 3,173	$ 2,197
Minimum [Member] | Machinery and equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	3 years
Minimum [Member] | Furniture and fixtures [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	3 years
Minimum [Member] | Generators [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	1 year
Maximum [Member] | Machinery and equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	7 years
Maximum [Member] | Furniture and fixtures [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	7 years
Maximum [Member] | Generators [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category	3 years